The objective of the proposed research is to identify and characterize in rat hepatoma tissue culture cells those membrane and secretory glycoproteins whose level can be altered by hormones. particularly by glucocorticoids, glucagon, insulin and growth hormone. The surface localization of the membrane proteins is verified by external labeling of the cells. We have shown that glucocorticoids alter cell adhesiveness, carbohydrate uptake and composition of membrane and medium glycoproteins. A corresponding hormone induced alteration in liver cells will be investigated and correlated to events during either development or inflammation. No significant changes in both function and composition of the plasma membrane were induced by the peptide hormones in the hepatoma cells. To determine whether the responsiveness can be restored, membrane vesicles carrying the appropriate hormone receptors will be experimentally inserted into the surface of the hepatoma cells. A second approach will be the use of hepatocyte-hepatoma hybrid cells. Variant hepatoma cells have been and will be selected for differences in adhesiveness or other cell membrane functions in response to hormone treatment. The surface membrane polypeptide composition and metabolism in these cells will be examined in the hope of defining causal relationships between the presence and absence of specific plasma membrane proteins and cell behavior, such as adhesiveness or cell-cell aggregation.